Kudos to BMW's design team for even designing a KEY so seamless and tight-fit that you can't see where it's supposed to come undone (Mercedes as usual a little more crude and behind the times in implementation.... ironically therefore making it easier to obviously see the actual key and how to un-click it ).

The boffins at BMW are probably still labouring under the misapprehension that people who buy their cars will read the first couple of chapters of the user manual